Web-guiding apparatus



Dec. 16, 1958 B. BACKLERT ET AL WEB-GUIDING APPARATUS 2 Sheets-Sheet 1Filed April 4, 1957 FIG./

INVENTORSZ B ROR BACKLERT BENGT LANNE SVEN WA LLIN BY ATTYS 2Sheets-Sheet 2 Filed April 4, 1957 INVENTORSI BACKLERT GT LANNE N WALLIN)m/ Unite States Patent WEB-GUIDING APPARATUS Bror Backlert, Bromma, andBengt Lanne and Sven Wallin, .l'onkoping, Sweden, assignors toAktiebolaget Svenska Flaktfabrilten, Stockholm, Sweden Application April4, 1957, Serial No. 650,731

Claims priority, application Sweden April 7, 1956 6 Claims. (Cl. 34-122)The present invention relates to apparatus for treating web material ina plurality of parallel runs having a turning roll disposed between theruns at each of the turning points for the web. More particularly, theinvention relates to an arrangement for automatically guiding thematerial while threading the same through the apparatus, the turningrolls of the apparatus being in the form of perforated cylinders andincluding a tie vice for connecting the interior of the cylinders with asource of vacuum.

When drying or other treating of material webs of for instancecellulose, paper or fabric, the web is guided in zigzag runs through thetreatment chamber for the purpose of saving space. Apart from the factthat the web is conducted mechanically through the chamber by means of anumber of endless transporting means or is conducted air-borne throughthe chamber, i. e. by blowing a gaseous medium towards the lower side ofthe web, there is a need of rotating rolls, so called turning rolls, fortransferring the web from one transport passage or run to another.During the threading of the web, the turning rolls are positively drivenand can be perforated and exposed to vacuum, whereby the web is suckedagainst the roll and follows the same, but after about half a turn, theend of the web must again be released from the roll. For a similarpurpose there are rotary vacuum rolls with stationary partitions thereindividing the surface of the roll so that vacuum is only obtained withinthe desired part of the circumference. In such cases a sufiicientsealing between the stationary partitions and the rotating roll may beobtained as the length of the roll as a rule is relatively short. In thepresent case, however, the length of the roll is great in relation tothe diameter of the roll (8:1 or more). It is difiicult to obtain asufficient sealing between the surface of the roll and the partition dueto said length, and furthermore because no braking friction worthmentioning can be allowed. This is due to the fact that when the drieris running, the turning rolls are driven only by the web and thus itmust be possible to disconnect the positive drive to the turning roll.The present invention relates to a new and improved arrangement inapparatus of the above mentioned kind, wherein the aforementioneddrawbacks will be eliminated.

The apparatus made in accordance with the present invention ischaracterized by a turning roll between the transport passages or runsat each of the turning points for the web, in combination with devicesfor blowing a gaseous medium against the web, the devices being arrangedin pairs adjacent each turning roll. The rolls, in accordance with theteaching of the prior art, are formed as a hollow perforated cylindricalshell and are connected at at least one of their ends to a suctionand/or a pressure chamber. The medium from one of the blowing devices isdirected towards the turning roll close to the point where the web atfirst comes into contact with the roll, and the medium from the otherblowing device is supplied at the point where the Web ice leaves theroll and is directed toward the web obliquely forwards in the intendedtransport direction.

According to a preferred embodiment of the invention each turning rollis provided with a number of' radial partitions dividing the roll into anumber of equal sectorshaped, lengthwise extending separate channelswith their ends open towards the suction and pressure openings in thechamber wall which confront against the roll. Furthermore the openingsin the wall confronting against the end of the turning roll areseparated by sealing plates for the radial partitions of the roll, theopenings being in the form of two sectors situated substantiallyopposite each other and having a centerangle at least of the same sizeas the center angles of the sector-shaped channels of the roll.

The invention can be carried out in apparatus having a blowing boxunderlying the horizontal runs of an airborne material web to supplygaseous medium to support the same. Such an embodiment is characterizedin that the devices for blowing gaseous medium against the web at theturning rolls consist of nozzles arranged in the walls of a chamberwhich is formed as an extension of the blowing box. The chamber isconnected to the blowing box by means of a damper-regulated opening.

The invention will now be described more in detail with reference to theaccompanying drawings, in which Fig. 1 illustrates a longitudinalsection through a roll in accordance with the invention.

Fig. 2 illustrates a cross section through the turning roll along theline 22 in Fig. 1.

.Fig. 3 illustrates a cross section along the line 33 in Fig 1.

Fig. 4 illustrates a perspective view partially in section through apart of a treatment chamber provided with a turning roll according tothe invention and with devices for blowing a gaseous medium against theweb.

Fig. 5 illustrates a longitudinal section of a modifi cation in whichthe material web is air-borne.

In the drawings, reference number 1 designates a weblike material andreference number 2 a turning roll for this web, which turning roll isformed as a cylinder having perforations 4 and supported by a shaft 3.According to the invention the turning roll is provided with a number ofradial partitions 5, dividing the roll in a number of equalsector-shaped, lengthwise extending, separate channels 6. The turningroll, at at least one of its ends is equipped with a flange '7 havingmachined surfaces and sealing against a corresponding surface 8 of ahood 9. By means of a partition 12 the hood is divided into a suctionchamber 10 and a pressure chamber 11. Said chambers are provided withopenings 13 and 14 in the chamber wall facing the end of the turningroll in such a manner that the channels of the roll during its rotationcan be caused to communicate alternatively with the suction and pressurechambers respectively. The apparatus can be modified so far that only asuction chamber is present, which connects with the channels whosecylindrical surfaces are covered by the web, whereas the oppositesituated channels are directly connected with the surroundingatmosphere. Reference numbers 15 and 16 designate two sealing surfacesarranged between the openings 13 and 14- respectively, with whichsurfaces the radial partitions 5 of the roll are in contact. The sealingsurfaces'consist of two sector-shaped plates situated substantiallyopposite each other and having a centre angle at least of the same sizeas the channels of the roll. By this arrangement always at least oneradial partition will bear against each of the surfaces during therotation of the roll and thus prevent the possibility of any of thechannels connecting simultaneously with both the suction and thepressure chambers.

In Fig. 4 the reference number 1 likewise designates the material weband reference number 2 the turning roll for said web. Reference number17 designates a device for blowing a gaseous medium towards the turningroll close to the point where the web at first comesinto contact withthe roll. In the embodiment illustrated in Fig. 4, said device isdesigned as a tube parallel to the turning roll and provided with alengthwise extending slot 18. or, if desired, a corresponding series ofholes (not shown). Reference number 19 designates a device in form of ablowing box arranged at the opposite side of the turning roll, the sideof said box facing the roll being equipped with a number ofeyelid-shaped perforations for blowing a gaseous medium obliquelyforwards towards the web in the intended direction of movement of theweb. Reference number 21 designates a wall in the treatment chamber forthe web. During the threading of the web the devices 17 and 19 areconnected with a fan (not shown in the drawing) or a similar device forsupplying a gaseous medium thereto.

In the modification illustrated in Fig. the reference number 1 likewisedesignates the material web and reference number 2 designates theturning roll for said web. In this case, the web is air-borne by blowinga gaseous medium towards the web by means of a blowing box 22 designedfor instance in accordance with the Swedish patent. specification135,206 which corresponds to U. S. Patent 2,678,237. In this case thedevices designated 17 and 19 respectively in Fig. 4 are replaced bydevices formed in a chamber 24 which is an extension of the blowing box22. A damper-regulated opening 25 connects the chamber 24 with theblowing box 22 during the threading of the web for blowing a gaseousmedium towards the turning rolls through the openings 26 and 23respectively for the above mentioned purpose.

What we claim is:

1. In a conveyor system for transporting a continuous open-width webziz-zag in at least two spaced parallel runs, apparatus for changing thedirection of travel of the leading free end portion of the web andguiding the same from the first run to the second run comprising incombination, a hollow turning roll mounted between the runs at one endthereof with its axis substantially parallel to said runs fortransferring the leading end of the web from the first to the secondrun, said roll comprising a perforated cylindrical shell, means to drivesaid roll during transfer of said leading end, a pair of devices forblowing jets of gaseous medium against the web, the first of saiddevices being positioned to direct a jet of medium toward said rollsubstantially radially thereto at the point where the web initiallycontacts the roll in its travel from the first run, the second of saiddevices being positioned at the point where the web leaves the roll andoperable to direct a jet of medium towards the web obliquely forward inthe direction of travel of the web in the second run, suction means toapply suction to at least a segment of the interior of said cylindricalsurface as it travels from said first to said second device to engageand support the web thereon, and means to remove the suction from thesegment as it travels from the second to the first device.

2. Apparatus according to claim 1 including pressure means associatedwith said suction-removing means to supply a gaseous medium underpressure to a second segment of the interior of said cylindrical shellintermediate said second and first devices to positively disengage theleading free end portion of said web from said perforated shell uponpassage thereof beyond said second device to afford travel of saidleading free end portion into said second run.

3. Apparatus according to claim 2 wherein the turning roll is providedwith a number of radial partitions dividing the interior of the rollinto a number of equal sector-shaped lengthwise-extending separatechannels open at at least one end, a chamber wall slidably engaging saidpartitions at said one end and defining two openings operable tocommunicate with said channels during rotation of said roll, saidopenings being separated by sealing surfaces engaging the radialpartitions of the roll in the form of two sector-shaped wall portionsdisposed substantially diametrically opposite each other, each wallportion having a center angle of at least the same size as the channelsof the roll and operable to register therewith, whereby upon rotation ofsaid roll each channel communicates alternately with said openings, saidpressure means being connected to one of said openings and said suctionmeans being connected to the other of said openings whereby uponrotation of said roll, the channels are connected alternately topressure and suction.

4. Apparatus according to claim 3 wherein said chamber wall constitutespart of a double chamber having a partition therein for separating thesame into a pressure chamber and a suction chamber respectively, saidopenings being positioned on opposite sides of said partition means ofthe double chamber.

5. In a conveyor system for transporting a continuouswidth web zig-zagin at least four spaced parallel runs, apparatus for changing thedirection of travel of the leading free end portion of the web andguiding the same from the first run to the second run and from the thirdrun to the fourth run comprising in combination two hollow turningrolls, each comprising a perforated cylindrical shell, the first of saidrolls mounted between the first and second runs at one end thereof withits axis substantially parallel to said runs for transferring theleading edge of the web from the first run to the second run, the secondof said rolls mounted between the third and fourth runs at said one endthereof with its axis substantially parallel to said runs fortransferring the leading end of said web from the third run to thefourth run, means to apply suction to at least a segment of the interiorof said shell of each roll to engage and support the web thereon, meansto drive each roll during transfer of said leading end, a pair ofblowing devices for each roll for blowing jets of air against the webadjacent each turning roll, the first of said devices being positionedto direct a jet of air toward said roll substantially radial thereto atthe point where the web first comes into contact with the roll, thesecond of said devices being positioned at the point where the webleaves the roll and operable to direct a jet of air towards the webobliquely forward in the direction of travel of the web in thesucceeding run, an air supply box intermediate said second and thirdruns having a perforated upper side underlying the second run forproviding a cushion of air supporting said run, an extension chamberconnected through an opening to said air supply box and disposedintermediate said first and second turning rolls, and a damper in saidopening to regulate the same, said first blowing device associated withsaid second turning roll consisting of nozzle means in a wall of theextension chamber directed substantially radially to said second roll.

6. Apparatus according to claim 5 wherein the second blowing device ofthe first roll comprises oblique openings in the upper wall of saidextension chamber for directing jets of air obliquely forward in thedirection of travel of the web in the second run.

References Cited in the file of this patent UNITED STATES PATENTS776,197 Nistle Nov. 29, 1904 1,779,611 Merrill Oct. 28, 1930 2,532,910Hayward Dec. 5, 1950

